Sheridan Smith may be a critically acclaimed actress, but she feels like she is "totally blagging it through life".

The star, who won a Bafta for her performance as Great Train Robber Ronnie Biggs's wife, said while her "formally trained" co-stars will have scripts covered in writing, hers will be covered in "coffee stains and fag burns".

Smith said she has acquired self-doubt as she has become more successful.

Speaking to the Sunday Telegraph's Stella magazine, she said: "It's just to do with my ability. When I'm working alongside someone like Dame Maggie Smith I can't help thinking, 'I don't deserve to be here'."

She added: "I spend most of the time feeling like I'm totally blagging it through life."

Smith also joked it is unlikely that she will go off to Hollywood to become a "juice-drinking jogger".

The actress is starring as Cilla Black in Cilla, an ITV drama series exploring the rise to fame of the Liverpudlian star.